Food Protein-Induced Enterocolitis Syndrome (FPIES)

What is food protein-induced enterocolitis syndrome (FPIES)?

Food protein-induced enterocolitis syndrome (FPIES) is a rare food allergy that affects the gastrointestinal (GI) tract. Unlike most food allergies, symptoms of FPIES do not begin immediately after eating. Instead, it can take hours before severe symptoms begin.

The most common FPIES food triggers are cow’s milk, soy, rice and oats, but any food can cause FPIES symptoms. Typical symptoms of FPIES include severe vomiting, diarrhea and dehydration two hours after eating. These symptoms can lead to other complications, including changes in blood pressure and body temperature, lethargy, and failure to thrive.

FPIES is commonly misdiagnosed as a severe stomach bug because the symptoms are so similar. It is generally only after repeated ingestion of the trigger food — followed by severe symptoms hours later — that indicate FPIES may be the cause.


When a child with FPIES eats a trigger food — whether it is milk, rice, oats or another food — symptoms develop. When the trigger food is removed from the child’s diet, FPIES symptoms subside.

The age in which FPIES symptoms begin to develop depends on a variety of factors but in general, infants who are bottle fed show symptoms earlier than infants who are exclusively breastfed. For bottle fed infants, FPIES reactions may begin in the first few months of life if reactions are due to milk, soy, or, at times, rice.

For exclusively breastfed infants, FPIES reactions generally only begin when other foods are added to their diet. However, we have had babies who do not tolerate foods in maternal diet (although reactions are not as severe.) Typically, the child must directly ingest the trigger food for symptoms to develop.

Signs and symptoms

Symptoms of food protein-induced enterocolitis syndrome can vary from child to child and in severity. Symptoms may include:

  • Vomiting, typically occurring two hours after ingestion
  • Diarrhea that begins after vomiting
  • Dehydration
  • Severe lethargy
  • Changes in blood pressure and body temperature

For the majority of children with FPIES, growth is normal and the child is healthy as long as he or she avoids trigger foods. For children with chronic FPIES, there may be growth concerns or concomitant gastroesophageal reflux.

Testing and diagnosis

Diagnosing FPIES can be challenging. It can be difficult to find the specific trigger food or foods affecting your child, as symptoms don’t develop immediately after ingestion. Some children with FPIES may also have an additional food allergy, which can complicate appropriate diagnosis.

Additionally, sometimes FPIES triggers do not show up on standard allergy tests such as a skin prick test (SPT) or a blood test that measures food IgE antibodies (RAST). A negative allergy evaluation may actually delay the diagnosis in some cases because a food trigger (such as cow’s milk) may be incorrectly eliminated as a cause of the delayed symptoms that FPIES produces.

At The Children’s Hospital of Philadelphia, an FPIES diagnosis is generally made by an experienced allergist or gastroenterologist who considers the child’s medical history and symptom presentation, and by excluding other possible illnesses.

Other tests that may be performed include:

  • Blood tests — Tests performed during a reaction may be helpful; the results may mirror the child’s response to infection.
  • Supervised oral food challenge test — The child is given the food that is the suspected “trigger” in a controlled, clinical environment and monitored for a response.


Every child’s FPIES reaction is different, so treatment is determined on a case-by-case basis. At Children’s Hospital, we practice collaborative, family-centered care. A team of expert clinicians — including leading allergists, gastroenterologists, pediatric nurses, feeding therapists and others — will partner with you in the care of your child.

For example, infants who have reacted to dairy and soy-based infant formulas may be placed on hypoallergenic or elemental formula. Breastfeeding infants who begin exhibiting FPIES symptoms when solids are introduced into their diets, may return to strictly breastfeeding. Other children — with fewer food triggers to an FPIES reaction — may be able to simply avoid eating those foods.

If a child experiences a severe case of vomiting, dehydration and/or changes in body temperature, the child should be seen immediately by a physician to avoid shock. In emergency situations, the primary treatment for an FPIES episode is intravenous fluids for rehydration.

Steroid treatments may also be used to lessen an immune reaction. Those treatments will help lessen the FPIES reaction, but they won’t treat the condition. Treatment for FPIES must be individualized and is often modified as the child grows.

Determining if a child has outgrown a trigger food is something that needs to be determined on a food-by-food basis. New foods are generally introduced into the child’s diet very slowly.

At CHOP, we introduce foods to patients during an in-office food challenge when we think the child may have outgrown the allergy or if the history is unclear. We can monitor the patient during ingestion and in the hours afterwards.

If the child passes the in-office part of the food challenge, families are instructed to slowly increase the amount of food the child eats until full serving size is reached.

Doctors generally recommend trialing one food slowly before introducing a new food. Individual recommendations will be given for your child.


For most people, FPIES is not a life-long condition. In fact, many children outgrow the condition by age three.

In one recent FPIES study:

  • 100 percent of children with barley as their FPIES trigger food outgrew the condition by age three
  • 60 percent of children with a dairy FPIES trigger outgrew the condition by age three
  • 40 percent of children with rice as their FPIES trigger food outgrew the condition by age three

Some children continue to experience FPIES symptoms into adolescence and beyond. With proper medical attention and a personalized dietary plan to ensure proper nutrition, children with FPIES can grow and thrive. 

Research into FPIES

Clinicians at The Children's Hospital of Philadelphia are leading FPIES research efforts worldwide. In 2010, the Hospital helped establish the FPIES United Family Fund, the first and only grassroots research fund for FPIES. By better understanding the pathophysiology of FPIES, we hope to develop new and improved treatments for the condition.

Many families, across the globe have traveled to CHOP in search of a diagnosis and treatment plan for their FPIES child. Together, these families have supported CHOP and the FPIES United Family Fund, by hosting benefits and events to create new funding for FPIES research.

Reviewed by Terri F. Brown-Whitehorn, MD